Rocket engines for usable BP?

[lucky13]

I've searched the hell out of Google and the forum, but can only find small bits of info.

What I am wondering is if the BP used in model rocket engines can be extracted and used to reload rifle cartridges or in cap and ball pistols?

Judging by the performance of the engines, it looks like it would perform well enough to throw a small bullet.

I know I could make my own BP but I would rather buy the engines for convenience and ease of storage if possible. If it is possible to use it, are there any other fillers inside or are they just BP?

Thanks :)

[pearlcrash911]

If it is possible to use it, are there any other fillers inside or are they just BP?


It is not only BP in the engine, it is also mixed with dextrine.

I don't know if it could be used for reloading weapons, but personally I would not want to spend a dollar to fill every five shells.

[Bert]

Estes engines are made from GOEX meal powder for the propellant grain, no binder is used.

The delay/smoke tracking portion of the engine is meal powder with a good percentage of Sulfur added to slow the burn and make more smoke.

The ejection charge is grained powder, it looks like 3fg to me.

Godamn expensive way to buy black powder for shooting.

[deadman]

The assumption that the great performance of rocket propellant (I'm assuming Estes or Quest) would transfer over to an equally well munitions powder is common around people around me. RP is relatively tame compared with BP.

A rocket motor is designed specifically for providing gaseous thrust to propel itself without blowing up a cardboard tube. In the case of black powder, it can be much hotter without fear of destroying anything other than the desired target.

IIRC, Estes uses a low KNO₃ with an equal amount of sulfur and charcoal, and I do believe a small amount of dextrin.

[nbk2000]

If hobby store rocket engines are all you can get, then you make do with what you got to work with.

If, on the other hand, you have access to the appropriate materials, then it's just stupid to try improvising something.

[Bert]

The assumption that the great performance of rocket propellant (I'm assuming Estes or Quest) would transfer over to an equally well munitions powder is common around people around me. RP is relatively tame compared with BP. .This is often true of large BP motors made in paper cases. BP engines optimized for maximum thrust will use a strong case and highest Isp propellant possible. This will be a formulation essentially identical to the highest grade sporting BP, processed in a like manner for fastest burning with highest gas production- The degraded performance of fireworks rocket engines black powder is related to the use of cheaper or lighter cases and the aesthetic requirement for a spark tail, also frequently the desire to hand ram fuel in these flimsy cases without expensive and time consuming support sleeves and hydraulic equipment.


A rocket motor is designed specifically for providing gaseous thrust to propel itself without blowing up a cardboard tube. In the case of black powder, it can be much hotter without fear of destroying anything other than the desired target.Estes engines and similar are optimized for maximum performance. High quality tubes are used, with very high loading pressures. It is customary to use slower fuels with spark producing additives in fireworks engines, it is not done with these high performance model rocket engines where maximum throw weight and acceleration are the objectives. Another clue to the difference in the fuel from lower performance fireworks engines is the much shorter spindle the engines are pressed on, and the fact that they are capable of achieving such high performance with what are essentially end burners rather than traditional rocket spindle dimensions.


IIRC, Estes uses a low KNO₃ with an equal amount of sulfur and charcoal, and I do believe a small amount of dextrin.
Estes use STRAIGHT GOEX MEAL "D" WITH NO ADDITIVES OF ANY KIND for the fuel grain. Other ingredients are added to the delay grain only.

I suggest you go buy an Estes engine and carefully separate the fuel grain from the delay grain and weigh the fuel. Dissolve the nitrate out. Weigh the dry residue. Use a suitable solvent such as Carbon disulfide to dissolve out the Sulfur. Weigh the remaining charcoal. Check the first water extraction for the presence of dextrin- Report your findings.

[Cobalt.45]

This site seems to be one of the better sources of info on BP compositions in general. http://www.musketeer.ch/blackpowder/charcoal.html

They don't think very highly of GOEX or any of the other commercial black powders. Not surprising, as my powder out performs GOEX, and is on a par with Pyrodex and Triple 7.

The "secret" is in the charcoal. Good charcoal= decent powder, if you do your job. Bad charcoal= shit powder, no matter what you do or don't do.

Make your own, if possible.

[Bert]

GOEX is not the best BP ever made. It is better than Chinese though... It is highly CONSISTENT though, which is important for propellant use.

GOEX reportedly uses maple for charcoal now, Dupont used to have willow grown right on the premises.

By what measure does your homemade equal the performance of Pyrodex? a weight:weight velocity:velocity parity?

[Cobalt.45]

By what measure does your homemade equal the performance of Pyrodex? a weight:weight velocity:velocity parity?

It's about equal in muzzle velocity, 50 yard groups are about the same as Pyrodex.
Triple 7 has an edge in velocity, but doesn't group as well out of my Kodiak. My powder is not as consistant from shot to shot as I'd like, but is acceptable.

It's cheaper by far, but has all the drawbacks- fouling, stinky clean up, smoke. Also has more recoil.

A Pyrodex 50gr equivalent pellet weighs about 41gr. Triple 7 weighs about 34.1gr. My powder weighs less than what a powder measure indicates. 40gr indicated weighs about 31gr.

My performance "increase" may well be due to accurate powder measurement, but it is carefully made using willow charcoal.

Would the charcoal and the graphite coating of commercial powder be the difference?

[Bert]

How do you consolidate your homemade BP? How do you grain it, and what screen sizes for pass/retained do you use for shooting? And do you hyave access to a chronograph?

The fouling is variable both with the charcoal used and the method and degree of milling. Longer milling generally tends to decrease fouling-

It is possible that the apparent greater performance and higher recoil is related to your powder being less dense and therefore faster burning than the denser commercial powder of equivalent grain size.

[lucky13]

Thanks guys, it's interesting to finally hear some other comments on this subject for me.

nbk2000's post is especially relevant. Indeed so far my searching has turned up only rocket engines that may be able to provide an acceptable propellant.

I've heard mixed things about purchasing BP and Pyrodex here. Most say an explosives license is required for both, others say Pyrodex is freely available (not in my experience). Others still say that small quantities (<100g?) can be kept without restrictions at home.

If I could actually buy the stuff straight off the shelf, I definitely would. Unless someone can point me in the right direction or towards an equivalent, it's gonna remain a problem for me.

[Cobalt.45]

The fouling I mentioned is not excessive.

By "consolidate", do you mean "press"? If so, I use a hydraulic press.

The grain size depends on what I'm shooting. Generally 2f for long guns .45 and up, 3f for smaller long guns and pistols.

IIRC -20+30 mesh for 2f.

No chronograph. Estimated by point of impact.

Are you familiar with http://www.dtic.mil/ndia/2003gun/chen.pdf#?

Moderators, please delete this if too far from thread subject. No more "Black Powder 101"

[Smoakie]

Shooting and reloading are quite popular in the US. You can walk into any gun store and buy whatever amount of powder you want (black powder, pyrodex, smokeless). You might even be able to buy pyrodex from walmart during black powder season.

The only trouble you might have is if you are having it shipped. Even then all you have to do is pay more since it will be hazmat.

Oh, and if your 13, you might have a hard time convincing someone to sell it to you.

I find it hard to believe that you have firearms you are wanting to fire or reload and have never walked into a gun store to purchase the powder. I mean the bullet reloads and the powder are sitting on the same shelf.

[nathan]

I don't see why you would want to use an expensive, inconvenient way of obtaining BP but there is no reason it shouldn't work.

The Estes rocket engine uses 75% Potassium Nitrate 10% Sulfur and 15% Charcoal.
The high performance must come from the method of processing.

There are no additives for a binder as far as the MSDS (http://kauai.hawaii.edu/msds/files/cjx/cjxtf.html) is concerned.

[Bert]

Shooting and reloading are quite popular in the US. You can walk into any gun store and buy whatever amount of powder you want (black powder, pyrodex, smokeless). You might even be able to buy pyrodex from walmart during black powder season.

Oh, and if your 13, you might have a hard time convincing someone to sell it to you.

If you tell them you are doing anything other than shooting a muzzle loader or cannon, they can't sell it to you unless you have an ATFE license for your proposed use.

[Smoakie]

If you tell them you are doing anything other than shooting a muzzle loader or cannon, they can't sell it to you unless you have an ATFE license for your proposed use.

I would hope he wouldn't tell them he was going to be making pipe bombs. He did mention some firearms so I thought that was his intended use which would make each shot pretty darn expensive.

Make sure you don't put smokeless in that muzzle loader, only black powder and pyrodex.

Also, I was in walmart and they do carry 1 lb bottles of pyrodex in the hunting section.

[lucky13]

If you live in a country where BP requires a license and you dont have one, then purchasing straight off the shelf is not an option.

Muzzle loading guns are not hard to get hold of at all, but the BP is.

As a side note, I have found 12 gauge blank shells that are filled to the brim with pure BP. Fairly inexpensive for the yield you get and are very easily opened. These are also very easy to buy in most countries I imagine.

[20920474]

I have used model rocket engine "blackpowder" before for little C02 bombs. The powder itself works to a fair degree but is very expensive for what you get.

[lucky13]

I agree, they are relatively expensive. But for satisfying a curiosity where you do not want a large amount of powder and are not planning on using it too often, I find such purchases ideal.

I know that I could make it, or buy it in large quantities with a license but I really don't feel the need to do either. I set myself a goal and achieved it, which I am happy with :)

For anyone interested, it is indeed possible to use it for reloading in a situation where you may not have powder to hand. Plus, as I mentioned before, it is very safe and easy to store.

[Cobalt.45]

ESTES C-class rocket engine propellant
Source: rec.pyrotechnics, Composition from 1994 US Dept. of Labor Material Safety Data Sheet.
Comments:
Preparation:

Potassium nitrate.................................71.79
Sulfur............................................ 13.45
Charcoal.......................................... 13.81
Dextrin........................................... 0.95

As you can see, the formula isn't ideal for use as gun powder. It's a little light on oxidizer and a little heavy on sulfur.

The >1% dextrin can be ignored, for all practical purposes.

It will work, though.

If used as an alternative propellant, clean your firearm after each use.

[neeka]

I've used rocket engine powder for my pvc pipe shotgun. It works perfectly as gunpowder for that kind of use. However, if you want to use it for real guns, I suggest you use real gunpowder.

+++++++++

I suggest that you capitalize the letter I when referring to yourself, if you wish to continue being a member here.

NBK

[NoltaiR]

This is certainly an interesting thread since you are trying to unload the propellant from a rocket engine for use in rounds. Usually I would expect the other way around since cartridges are easier to come by.

Anyways aside from the already stated fact that rocket engines have a polymer added to make the powder into a solid, the grade of propellant is severely different.

In a cartridge you want the propellant to go from solid to gaseous as fast as possible. While in a rocket engine you want to slow it down quite a bit.

Also you mentioned that you know that you can make your own BP.. so why not? You can make several pounds of it at a time and when practice you will learn how to increase and decrease your burn-rate based on purity of chemicals used and how stoichiometric you are.